1. Field of the Invention
The present invention relates to a joint member that is fixed between the vertically adjacent external wall panels when an external wall panel is fastened to an external wall portion of a building.
2. Description of the Related Art
In order to improve a design of the external wall of a building, an external wall panel such as fiber reinforced cement siding having a surface pattern of, for example, a natural stone style or a brick style, is fastened to the external wall portion of the building. As a manner of fastening an external wall panel to a side of the building frame, there is a method called a horizontal boarding to put the longitudinal side of the panel in a lateral (horizontal) direction. Another method called a vertical boarding calls for fastening the panel with its longitudinal side put in a vertical direction (from up to down). The external wall panels used for the vertical boarding normally have flat upper and lower end surfaces, and shiplap portions at the right and left ends. Thus external wall panels adjacent to each other at their right and left ends are joined edge by edge via the shiplap portions. On the other hand, joining the external wall panels adjacent to each other vertically requires an appropriate member that intervenes between the ends of the external wall panels.
FIG. 7 is a cross sectional view showing an example of a joint portion between upper and lower external wall panels fastened by vertical boarding. This example shows that the vertically adjacent external wall panels 30A, 30B are fastened to a lateral furring strip 91 by means of a nail 95 while a convex portion 42 of a hat joiner 40 is sandwiched between the said external wall panels. A sealing material 97 is filled over the hat joiner 40. The lateral furring strip 91 is fixed to a post or a stud (not illustrated) via a building paper 93. The hat joiner 40 is composed of a base plate 41 that serves as a fixed surface to the lateral furring strip 91 and the convex portion 42 that protrudes to the surface side of the base plate 41, and by using this hat joiner 40, a desired space is formed between the upper and lower external wall panels 30A and 30B.
FIG. 8a shows another construction example of a vertical boarding. According to this construction example, the upper and lower external wall panels 30A and 30B are fastened with an intermediate throating 50 sandwiched therebetween. The intermediate throating 50 is composed of a base plate 51 that serves as a fixed surface to the lateral furring strip 91, a step portion 52 that is formed at the lower end of the base plate 51, and a throating portion 53 that extends from the lower end of the step portion 52 to the surface side. As shown in the drawing, the lower end of the upper external wall panel 30A is mounted on the step portion 52 of the intermediate throating 50 with the throating portion 53 protruding from the space between the upper and lower external wall panels 30A and 30B to the surface side. Then, the external wall panels 30A and 30B are fixed to the lateral furring strip 91, with nails 95 driven through the surfaces of said external wall panels.
Further, as an example similar to the intermediate throating 50, an intermediate throating without the step portion 52 is also used in many cases.
FIG. 8b shows still another construction example of a vertical joint portion (refer to Patent document 1). In FIG. 7 and FIG. 8a, the external wall panels 30A and 30B are fastened by using the nail 95, however, in the construction example shown in FIG. 8b, an intermediate throating 60 fixed between the upper and lower external wall panels 30A and 30B holds the upper and lower ends of said panels 30A and 30B, and fastening members (not illustrated) fasten the right and left shiplap portions of the external wall panels 30A and 30B so as to fix said panels at the side of the building frame. The intermediate throating 60 consists of a base plate 61 that serves as a fixed surface to the lateral furring strip 91, and a support plate 62 and a throating portion 64 that extend from the base plate 61 toward the surface side to form two front surface plates 63 and 65 extending upwards and downwards respectively from the front ends of these support plate 62 and throating portion 64. As shown in the drawing, the support plate 62 and the front surface panel 63 cover and hold the lower end of the upper external wall panel 30A. In addition, the throating portion 64 and the front surface plate 65 cover the upper end of the lower external wall panel 30B.
[Patent document 1] Japanese Patent Application Laid-Open No. 2000-160804
The construction structure shown in FIG. 7 has a problem with a decay durability of the sealing material 97, and it is feared that rain water penetrates through the sealing material 97 and may causes a separation phenomenon of the sealing material 97. In addition, the sealing material 97 is filled between the upper and lower external wall panels 30A and 30B, making it difficult to form a joint groove portion with a depth, causing a problem with a design of the joint groove portion.
In the construction structure shown in FIG. 8a, it is necessary to adjust the positions of the external wall panel to obtain a desired certain width of the joint portion that, in other words, amount to the interval between the upper and lower ends of the external wall panels 30A and 30B, and this proved troublesome in performing the construction work. In addition, the throating portion 53 of the intermediate throating 50 covers the front surface of the upper end of the lower external wall panel 30B and a joint groove portion that is well-shaped in a horizontally straight line is hard to obtain. As a result, the appearance of the surface patterns of the upper and lower external wall panels 30A and 30B is divided by the throating portion 53.
In the construction structure shown in FIG. 8b, the shape of the intermediate throating 60 is complicated, and in order to support the weight of the upper external wall panel 30A, it is necessary to make the intermediate throating 60 into an aluminum molded item and its manufacturing cost is expensive. Further, in order to hold the vicinity of the lower end of the external wall panel 30A stably, it is necessary for the upper front surface plate 63 to have a relatively large width and consequently, the width of the lower front surface panel 65 is also exposed largely to the front surface of the upper end of the external wall panel 30B. As a result, the appearance of the surface patterns of the upper and lower external wall panels 30A and 30B is clearly divided.